In drive trains for vehicles which include an engine-driven flywheel coupled to a transmission through a clutch, a disc is disposed between the clutch plate and flywheel. There is a tendency for rattling to occur in drive trains of vehicles during both idle and drive modes. The rattle is caused by excessive torsional vibration in the drive train and may be compensated for by a decrease in the elastic rate of the drive train while in its nominal operating range and an increase of travel and torque capacity of a damper associated with the drive train.
The problem has been recognized and addressed in the prior art by coupling the disc to a hub with a damping spring assembly, which spring assembly may include an array of single, helically disposed springs or an arrangement of spiral springs. While these approaches address the problem, they have not done so in a way which is completely satisfactory by adequately lowering the elastic rate of the damping spring assembly while raising the total travel and torque capacity of the damping spring assembly.